Currently, a verification code, also referred to as Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHA), is widely used as a secure verification method. The verification code can be used to determine whether an operator is a user or an unauthorized program. The verification code can prevent unauthorized operations such as a malicious attempt to log in to a user account, cracking of a user password through enumeration, or sales volume manipulation or speaking through script control.
In the existing technology, to prevent the unauthorized program from automatically recognizing the verification code, a method for displaying the verification code is increasingly complex. The verification code is usually displayed by using the following methods: In a first method, as shown in FIG. 1a, the verification code is expressed by using a number or a text, and a background is added into a verification code display area, or the number or the text is distorted, to improve interference of the verification code. In a second method, as shown in FIG. 1b, a plurality of pictures and prompt information are provided, so that the user recognizes a corresponding quantity of specific pictures from the plurality of similar pictures based on the prompt information.
However, in the previous methods, the verification code is displayed by using a relatively complex method. Although an unauthorized script's automatic recognition can be interfered with, additional interference is also caused to the user. In other words, after the previous verification code is displayed to the user, a possibility that the user incorrectly recognizes the verification code increases. If an error occurs, the user needs to refresh the verification code and continue to recognize the newly generated verification code, until the verification succeeds. Apparently, the previous verification process in the existing technology possibly takes a long time. In particular, when a recognition error occurs, the user needs to repeatedly perform verification.